When to use a layout program vs. an illustration or photo-editing program for your layout:

Layout programs, such as QuarkXPress and InDesign, are better for projects with multiple pages and relatively more body text, especially if that
body text goes through the whole project.

Illustration and photo-editing programs, such as Adobe Illustrator and Photoshop, are better for projects that have only 1 or 2 pages, and are
dominated by graphics and large type rather than body text.

Layout file

If you are working in an illustration program (such as Illustrator) or a photo editing program (such as Photoshop), we recommend that you

create your document at the full bleed size

create a separate file for each side of an item

If you are working in a layout program (such as QuarkXPress or Adobe InDesign) we recommend that you

create your document at the trim size and include the specified amount of bleed for your product (.125")

use the same file for each side of an item, and label the pages "FRONT" and "BACK" in the document

File resolution:

Layout file resolution should be 300 dpi at 100% of the final output size.

Image file resolution should be 300 dpi at 100% of the image's final output size.

CMYK vs. RGB

Print uses the CMYK color system (Cyan, Magenta, Yellow, and Black) — not RGB (Red, Green and Blue), which is meant for screen displays.

Create your document in CMYK mode.

Keep in mind that many of the bright values produced by your monitor cannot be reproduced in print.

How to make sure your document is CMYK in Adobe products:

InDesign:

Go to the Edit Menu and choose "Color Settings"

Make sure you are in Working Space: CMYK: "U.S. Web Coated (SWOP) v2." The RGB value will not affect your design.

Spot colors

Spot colors are printing inks of colors that are specially mixed according to a recipe. They are chosen from color matching systems and swatch books.
They are generally used as a complement to black or to achieve an exact color that CMYK process colors cannot provide.

Spot colors are optional. As a designer, some factors to consider in deciding whether or not to use spot colors are:

Cost/budget — spot colors added to 4-color job will significantly raise the cost. Carefully choose and define all colors in your files as
either CMYK or spot.

The practical limits of offset presses keep the possible number of color plates to 6 at most. When spot colors are used, a more typical run is a
2-color (black + spot) or a 5-color (CMYK + spot) job.

Inkd buyers will not necessarily print your design on offset presses as spot colors are intended for. This means that if a spot color you choose
is essential to a design you create, such as for a logo, you should note that in its description when you upload it. However, realistically,
buyers will sometimes opt for color digital printing anyway, which will automatically convert spot colors to CMYK.

Be sure that spot colors used in your graphics files are named exactly the same as in the layout file.